The present invention relates to a motor coil actuating the display means of a timepiece, said coil including a magnetisable core each of whose ends includes a lug, an insulating coil body formed of a tube surrounding the core and a flange disposed at each of the ends of the tube, and a winding wound around the body of the coil.
A coil whose structure resembles quite closely that which has just been described is shown in Patent Application JP 30712/86. This document also describes a core provided with two lugs, two flanges holding the winding and an insulating film surrounding the core. On one of the lugs is affixed a printed circuit with two paths each receiving an output wire of the coil winding. The coil and the place where the wires are connected to the circuit are covered with a protective coating. It is not clearly stated how these connections are achieved. One may imagine however that the wires are bonded with tin solder on the printed circuit paths in accordance with the standard method. Whatever, the connection of the winding output wires to the rest of the circuit always poses manufacturing problems. As a matter of fact, it should be known that the winding wire is extremely fine since diameters of the order of 20 .mu.m are currently used. A wire of such fineness is difficult to manipulate, very fragile and subject to frequent breakages which lead to the coil being discarded. Moreover, if the bonding is performed with tin solder, stripping of the wire is also a problem, which further increases the risk of breakage. Testing the proper manufacture of the winding after it has been wound by measuring the electric resistance is also a problem. Most of the time this test takes place after bonding of the wires onto the circuit paths, an operation which could be avoided if the test was made directly on the output wires before bonding.